Cleaning the Cooling System

A. De-oiling (only required if anti-corrosion oil was filled in).

1 Completely drain cooling system.
2 Remove thermostat element and set heater lever to warm.
3 Fill cooling system with a 5 % solution of water and P3 Standard (made by Henkel) (50 g P3/1 l water water).

Attention !
On vehicles with aluminum radiator, a neutral cleaner such as P3 Croni (made by Henkel) or Grisiron 7220 (made by Farbwerke Hochst) must be used instead of the heavily alcaline cleaner P3 Standard.

4 Run engine warm at medium speed up to approx. 80 °C (176 °F) and hold at this temperature for about 5 minutes.
5 Stop engine and permit cooling system to cool down to approx. 50 °C (122 °F).
6 Completely drain solution.
7 Immediately thereafter, fill cooling system twice with fresh water, run warm (approx. 5 minutes) and drain.


B. Decalcification, derusting

Attention! Prior to decalcification and if anti-corrosion oil was filled in, de-oil cooling system, even if no visible contamination by oil is present.

1 Top up cooling system with a 10% (100 g/l) solution from water and citric, tartaric or oxalic acid (to be obtained from the chemicals trade) while giving preference to citric acid.
2 Run engine warm at medium speed up to approx. 600 °C (176 °F) and hold for approx. 10 minutes at this temperature.
3 Stop engine and permit to cool down to approx. 50 °C (122 °F).
4 Completely drain decalcification solution.
5 Flush cooling system at least three times with fresh water, while running engine for at least 5 minutes with each flushing charge.

Badly calcified cooling systems may require a repetition of the treatment Always prepare a fresh decalcification solution and repeat flushing steps.

6 Install thermostat element with new seal.
7 Fill the cooling system with specified coolant. Specifications


NOTE: For decalcification and derusting, commercial products consisting of the acids named above may also be used.


Chromic cid or products containing chromates are prohibited by sewage regulations.